Electromagnetic switching devices and production methods for electromagnetic switching devices are generally known. In particular an electromagnetic switching device is known to have the following features:
The switching device has a switching chamber and a contact bridge carrier.
The contact bridge carrier is equipped with movable contact bridges.
The contact bridges comprise a number of primary contact bridges and at least one auxiliary contact bridge.
The contact bridge carrier is inserted into the switching chamber and supported there in such a manner that it can be displaced longitudinally in an actuation direction.
The switching chamber is equipped with fixed primary counter-contact points and fixed auxiliary counter-contact points.
Each primary counter-contact point interacts with one of the bridge contact points of one of the primary contact bridges and each auxiliary counter-contact point interacts with one of the bridge contact points of one of the auxiliary contact bridges.
Primary covers are fixed to the switching chamber, so that the primary covers cover the primary counter-contact points.
In the prior art the primary contacts are used to connect a load voltage (typically three-phase current of up to 690 V rated voltage—in individual instances even more—or direct current voltage of up to 500 V rated voltage—in individual instances even more) to a load. The primary contacts are generally configured as normally open contacts. The auxiliary contacts are used to pick off the actual switching state of the electromagnetic switching device. To this end the auxiliary contacts switch a monitoring voltage, which is often much lower than the load voltage. It is typically either 24 V direct current voltage or 100/110/230 V alternating current voltage. Even higher voltage values are possible in individual instances. The auxiliary contacts can alternatively be configured as normally open contacts or normally closed contacts.
Contact erosion occurs at the primary contacts during switching processes. Contact erosion means that the primary contacts wear out after a certain number of switching cycles. However contact erosion can also cause the function of the auxiliary contacts to be impaired, for example due to dirt or corrosion as a result of the penetration of aggressive gases, which result during contact erosion of the primary contacts. For this reason the primary contacts should be partitioned off as effectively as possible from the auxiliary contacts.
In the prior art it is known that the switching chamber can be configured in one piece and that ribs can be molded on the switching chamber. In contrast in this embodiment the contact bridge carrier has no ribs, etc. A so-called single labyrinth can be realized by means of this embodiment.
An electromagnetic switching device is known from U.S. Pat. No. 6,583,694 B2, wherein ribs are molded on both the switching chamber and on the contact bridge carrier, so that a so-called double labyrinth can be realized. However with this embodiment the switching chamber is made up of two parts, resulting in a greater manufacturing and assembly outlay.